Recent progress in exact and reduced-order modeling of light-scattering properties of complex structures

An emerging research area in biophotonics with potentially near-term clinical applications in early stage cancer detection involves the investigation of possible correlations of the elastic light scattering properties of tissues with alterations in their cellular composition and nanostructure. Until recently, exploring these correlations has been impeded by a lack of robust and accurate mathematical models of the light scattering properties of complex structures. In this paper, we review recent progress in this area. Topics include: 1) development of accurate reduced-order expressions for the total scattering cross section spectra of a wide range of nonspherical and inhomogeneous particles; 2) rigorous finite-difference time-domain modeling results showing how the backscattering of light can be sensitive to nanometer scale features embedded within micrometer-scale particles; and 3) development of accurate reduced-order expressions for the backscattering depolarization properties of a wide range of inhomogeneous particles. These advances provide an improved science base for cellular level biophotonics, and have promise to accelerate the development of novel corresponding clinical technologies.